This protocol is intended to develop techniques suitable for delineation of the post-transfusion survival and traffic patterns of autologous and allogeneic blood cells. It is intended as an omnibus protocol to utilize standard radiolabeling techniques applied to several formed blood elements, and to develop new techniques to aid clinical investigation of transfusion problems and to support research activities where cell survival and traffic studies are important. Information on the biology and immunology of transfused cells should accrue: prediction and documentation of survival and localization of these radiolabeled elements in patients should also be therapeutically useful.